F/X VisualizationsApril 03, 2010
Saying Goodbye to the Metrodome
By Dave Allen

Earlier today Jeremy chatted with Aaron Gleeman about the Twins and they noted Target Field, the new home of the Twins. It sounds like Aaron is pretty excited about it, as I am sure all Twins fans are. But I wanted to take a brief moment to note the passing of the Metrodome as the home of the Twins. I will do so in the same way that I did for the two New York parks this time last year and the only way I could think to do so: a run value map based on the Gameday recorded locations of balls in play and home runs at the Metrodome.

The locations are again taken from Gameday and then translated by Peter Jensen's factors. Gameday records where the balls are fielded not where they landed (Jensen has not yet released the 2009 transition factors so for 2009 I used the 2008 values). Each event (out, double play, single, …) is given its run value and then the run values for each location were fit using a loess regression. The the run value for each location, as predicted by the regression, was color coded. I have finally taken Studes' advice and flipped the color scheme so that blue is low (good for the pitcher) and red is high (good for the batter).
This is not meant as a serious statistical analysis (for serious analysis using the Gameday locations go to Jensen's series or hold tight for Colin Wyer's Gameday-based defensive metric), rather a pretty picture and a way to say goodbye to the Metrodome.


Is anyone using this sort of thing to refine park factors? I find most publicly available park factors to be too vague and/or inconsistent. I'm sure some teams have their own info that's more detailed.

and Helloooo Mosquitoes!